It is known to place samples on stages in ellipsometer and the like systems, and to cause a polarized beam of electromagnetic radiation to impinge on said sample at an oblique angle thereto, interact with said sample and then enter a detector. It is also known that the “tilt” of a sample surface at a specific location thereon can affect realized angle and plane of incidence values actually achieved. Further, it is known to adjust the vertical height of the stage to position a sample such that a beam of electromagnetic radiation reflecting therefrom enters a detector.
Existing Provisional and Utility Applications, (ie. 60/459,690 Filed Apr. 3, 2003 and Allowed application Ser. No. 10/652,696 Filed Sep. 2, 2003), by the Inventor herein, show a prior art system for detecting sample tilt, and a system which utilizes an ellipsometer beam reflected from a sample to perform vertical positioning of a stage. A beam splitter is used to divert a portion of the reflected beam into a detector and used to mediate adjustment of the sample's vertical position and/or tilt. Said system does not secure relative position of the ellipsometer and sample, but provides for aligning a sample system and controlling the angle and plane of incidence at which a beam of electromagnetic radiation obliquely impinges on a monitored location of a surface of a sample, and comprises, as viewed in side elevation:                a sample supporting stage which can be translated in “X”, “Y” or “Z” directions as well as rotated about “X”, “Y” and optionally “Z” axes;        vertically above said stage there being a first beam splitter means, a lens and a first camera means for providing a view of a portion of the surface of said sample, said first beam splitter means optionally having positioned on a lower surface thereof light emitting means for providing light to the surface of said sample;        laterally with respect to said first beam splitter means there being a reflection means;        vertically above said reflection means there being a second beam splitter;        vertically above said second beam splitter there being a second camera means and laterally with respect to said second beam splitter, there being sequentially a lens and an essentially point source of electromagnetic radiation;        said first and second camera means each having associated therewith display means.        Said system further comprises an ellipsometer polarization state generator to cause, and a polarization stage detector to monitor, a beam of electromagnetic radiation which in use impinges on said monitored location on said surface of said sample at an oblique angle thereto.        
In use said first camera means and its associated display means provide a view of at least a portion of the surface of a sample utilizing light provided by said light emitting means for providing light to the surface of said sample positioned on said lower surface of said first beam splitter, and said essentially point source of electromagnetic radiation provides electromagnetic radiation to the surface of said sample via said second beam splitter, said reflective means and said first beam splitter, and said sample supporting stage is caused to be translated in any of said “X”, “Y” and “Z” directions as well as rotated about said “X”, “Y” and optionally “Z” axes which are necessary to cause an interrogating beam of electromagnetic radiation provided by said essentially point source of a source of electromagnetic radiation to reflect from the surface of said sample, proceed back through said first beam splitter means, reflect from said reflective means, pass through said second beam splitter means, enter said second camera means and cause an image on the display means associated therewith which indicates that the monitored location on the sample surface is oriented so as to face substantially vertically.
The purpose of the foregoing is to align said sample surface to assure that said beam of electromagnetic radiation provided to said monitored location on the surface of said sample at an oblique angle approaches said surface at known intended angle of incidence and plane of incidence orientation, rather than at an angle of incidence and plane of incidence orientation which is modified by surface irregularities or non-flat samples.
Said system can further comprise a polarizer means in the path of said beam of electromagnetic radiation provided by said essentially point source of electromagnetic radiation, and in which said first beam splitter is sensitive to polarization state, and the polarizer means can be adjustable to enable control of the direction of polarization. The system point source of a source of electromagnetic radiation can comprise a fiber optic.
A related Co-Pending Application is Ser. No. 11/495,130 Filed Jul. 29, 2006 which describes a related system.
A patent to Abraham et al., U.S. Pat. No. 6,091,499 describes a method and system for automatic relative adjustment of samples in relation to an ellipsometer. Paraphrasing, said Abraham et al. system basically comprises:                a system for orienting a sample on a stage in an ellipsometer system comprising a first light source, a polarizer, said stage, an analyzer and a detector;        said system further comprising a detection system having a second light source, wherein said detection system is independently adjustable in relation to said ellipsometer, and wherein said detection system can be electronically locked into position relative to said ellipsometer so that said ellipsometer and said detection system can be adjusted as one unit in relationship to said stage, wherein said detection system can detect both a tilt of a sample placed onto said stage, and a distance of said sample from a coordinate source of the ellipsometer in two perpendicular axes; and        said system further comprising an adjusting device, wherein said adjusting device can adjust tilt of said stage, and wherein said adjusting device can adjust the position of said ellipsometer and detection system when in an electronically locked relationship with respect to one another.        
The 499 patent drawings show a single source, (identified as (21)), provides, via beam splitters and reflection means, normal and oblique angle of incidence electromagnetic beams to a sample, which normal and oblique angle of incidence electromagnetic beams are each intercepted by a different detector, (identified as (24) and (25) respectively), after reflecting from the sample. The associated ellipsometer system comprises a separate source, (identified as (11)).
Additional known patents are:                Patent to Coates U.S. Pat. No. 4,373,817;        Patent to Coates U.S. Pat. No. 5,045,704;        RE. 34,783 to Coates;        Patent to Mikkelsen et al., U.S. Pat. No. 6,600,560;        Patent to Fanton et al., U.S. Pat. No. 5,596,411;        Patent to Piwonka-Corle et al., U.S. Pat. No. 5,910,842;        Patent to Piwonka-Corle et al., U.S. Pat. No. 5,608,526;        Patent to Bareket, U.S. Pat. No. 5,889,593;        Patent to Norton et al., U.S. Pat. No. 5,486,701;        Patent to Aspnes et al., U.S. Pat. No. 5,900,939;        Patent to Aspnes et al., U.S. Pat. No. 5,9798,837;        Patent to Rosenscwaig et al., U.S. Pat. No. 5,412,473;        Patent to Carter et al., U.S. Pat. No. 5,771,094;        Patent to Liphardt, U.S. Pat. No. 7,136,162;        PCT Application Publication WO 99/45340;        Published Application of Stehle et al., No. US2002/0024668 A1.        
Need remains for additional systems and methods for orienting the vertical position, and tilt, of samples in ellipsometer, polarimeter, spectrophotometer and the like systems.